May 25 Does Vitamin C Actually Help Prevent or Treat the Common Cold?

Let’s take a quick second to review the data regarding the use of vitamin C to treat and prevent the common cold. Vitamin C is the most used supplement on the planet for this purpose. For that reason, it’s worth asking the question if it is effective.

The study I am going to reference is a meta-analysis of 29 different studies including 11,306 individuals that was published in 2013. A meta analysis looks at all the studies on a given subject and attempts to draw conclusions from them by combining all the data and looking for trends. It is the gold standard for aggregating data and drawing conclusions about study hypotheses. The link to that study is available below.

Question #1: Does vitamin C prevent the common cold?

In short, no. The study showed that regular supplementation with vitamin C did not significantly reduce the incidence of colds. However, there was a 50 percent decrease in the incidence of colds in a subset of patients exposed to vigorous activity, especially in extreme conditions (marathon runners, skiers, and soldiers in sub-arctic exercises). The reasons for the apparent benefit in this subset of patients are uncertain.

Question #2: Does vitamin C treat the common cold?

Vitamin C is often touted as a natural remedy for the common cold. The study showed a small but statistically significant 8 percent reduction in the duration of cold symptoms in adults regularly taking vitamin C supplements (at least 200 mg/day). The clinical relevance of this 8% is not known. The meta-analysis also showed that vitamin C given therapeutically after symptom onset did not reduce symptom duration or severity.

In conclusion, vitamin C does not prevent the common cold and reduces the the duration of the cold by only 8%. In a specific subset of patients who exercise vigorously, it does appear to have a preventative effect.